Hierarchy of Revit Family Creation Model Categories CATEGORY Includes elements that comprise the building model e. g. : Walls, Doors, Floor etc. A category controls the organization, visibility, graphical representation & scheduling options of families within the project Annotation Categories Includes items like text, dimensions and tags. FAMILY Within a category, a Revit family is a group of elements with a common set of properties or parameters represented graphically. Every element in Revit is created using families. 01 System Families 02 Loadable Families These are pre-defined families specific to a Revit Project. They can not be created in, deleted from, loaded into, or saved out of the current project. They can be created and loaded into a project as well as, deleted or saved from a project in the family editor using family templates. 03 In-Place Families These families are used to create one-of-a-kind element unique to project. Like System families they cannot be loaded into or saved out of a project. TYPE INSTANCE A type is a collection of variables (sizes, materials or other settings) saved to certain values and given a name for ease of reuse. It provides a convenient way to switch several variables of a family at once. An element created using a particular family & a specific family type is known as an instance. Instance parameters can be modified without changing family type parameters.